Incident Overview
On 10 September 2013, an Embraer E170-100 encountered flap system malfunctions during two separate flights. The aircraft was operating from Gdańsk Lech Wałęsa Airport (EPGD). No injuries were reported, and the aircraft landed safely both times.
First Incident
While descending for an approach at Gdańsk, the engine indicating and crew alerting system (EICAS) displayed a message "FLAPS LO RATE." Subsequently, during flap extension, a "FLAPS FAIL" indication appeared. The flight crew completed a landing on runway 29 with flaps at position 0 and slats at position 3. Upon landing, the crew requested fire services assistance as a precaution. The landing proceeded without further issues. After the flight, maintenance personnel performed fault isolation manual (FIM) procedure 27-51-00-810-802A, followed by an operational test of the flaps, which yielded positive results. The aircraft was then returned to service.
Second Incident
Later the same day, the same aircraft experienced another flap-related problem during climb after departing from Gdańsk. While passing flight level 150, the crew received a "FLAP LO RATE" warning along with an "ADS 1 HTR FAIL" indication. The flight crew decided to return to Warsaw Chopin Airport (WAW). The landing at WAW was uneventful, with the aircraft configured correctly for landing. After landing, the aircraft was handed over to technical services.
Maintenance Actions
Maintenance personnel performed mechanical and electrical rigging adjustments on the flap system in accordance with aircraft maintenance manual (AMM) procedures 27-50-00-820-801A and 27-50-00-820-802A Revision 36. A subsequent operational test per AMM 27-50-00-710-801A Revision 36 confirmed proper flap operation. On 13 September 2013, a technical test flight was conducted to verify the correction, with positive results.
The "ADS HTR FAIL" indication could not be reproduced during ground testing per AMM 30-31-00-710-801-A, but it recurred during the technical test flight. To address this, maintenance replaced Air Data Smart Probe number 2 according to AMM 34-13-01-04 Revision 37.
Cause
The investigation determined that the cause of the incident was a spontaneous misadjustment of the flap system.
Safety Recommendations
No safety recommendations were issued by the investigating body.